使用API获取Windows系统的文件关联图标

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#region 读取文件图标

[DllImport("shell32.dll")]

static extern uint ExtractIconEx(string lpszFile, int nIconIndex, int[] phiconLarge, int[] phiconSmall, uint nIcons);

/// <summary>

/// 给出文件扩展名（.*），返回相应图标

/// </summary>

/// <param name="fileType">文件类型</param>

/// <param name="isLarge">是否需要大图标，bool值</param>

/// <returns></returns>

Icon GetIconByFileType(string fileType, bool isLarge)

{

if (fileType == null || fileType.Equals(string.Empty)) return null;

RegistryKey regVersion = null;

string regFileType = null;

string regIconString = null;

string systemDirectory = Environment.SystemDirectory + "//";

if (fileType[0] == '.')

{

//读系统注册表中文件类型信息

regVersion = Registry.ClassesRoot.OpenSubKey(fileType, true);

if (regVersion != null)

{

regFileType = regVersion.GetValue("") as string;

regVersion.Close();

regVersion = Registry.ClassesRoot.OpenSubKey(regFileType + @"/DefaultIcon", true);

if (regVersion != null)

{

regIconString = regVersion.GetValue("") as string;

regVersion.Close();

}

if (regIconString == null || regIconString.Length <= 0)

{

//没有读取到文件类型注册信息，指定为未知文件类型的图标

regIconString = systemDirectory + "shell32.dll,0";

}

else

{

//直接指定为文件夹图标

regIconString = systemDirectory + "shell32.dll,3";

}

string[] fileIcon = regIconString.Split(new char[] { ',' });

if (fileIcon.Length != 2)

{

//系统注册表中注册的标图不能直接提取，则返回可执行文件的通用图标

fileIcon = new string[] { systemDirectory + "shell32.dll", "2" };

}

Icon resultIcon = null;

try

{

//调用API方法读取图标

int[] phiconLarge = new int[1];

int[] phiconSmall = new int[1];

uint count = ExtractIconEx(fileIcon[0], Int32.Parse(fileIcon[1]), phiconLarge, phiconSmall, 1);

IntPtr IconHnd = new IntPtr(isLarge ? phiconLarge[0] : phiconSmall[0]);

resultIcon = Icon.FromHandle(IconHnd);

}

catch { }

return resultIcon;

}